1. Field of the Invention
The present invention relates to an AC surface discharge type of matrix plasma display apparatus in which ultraviolet lights caused by discharge are applied to fluoresce to excite the fluoresce to emits lights in a space which corresponds to a colour of red, green, or blue and is formed by arranging partitions between substrates and particularly, relates to the AC surface discharge type of matrix plasma display apparatus in which color purity of white color emission is improved by suitably adjusting balance among the brightness of red, the brightness of green, and the brightness of blue which are simultaneously emitted. The AC surface discharge type of matrix plasma display apparatus is suitable for full-colour display.
2. Description of the Prior Art
FIG. 37 is a cross sectional view showing a structure of a typical conventional AC surface discharge type of plasma display panel (PDP) and FIGS. 38-40 are plan views or front views showing structures of principal parts thereof.
Referring to FIG. 37, pairs 7 of a scan electrode and a common electrode are disposed on front glass substrate 6 in row direction. Each of the pairs 7 is composed of beltlike transparent conductive sheets. Usually, metal electrodes not shown are connected to the scan electrodes and common electrodes in order to reduce resistance thereof. Further, transparent insulator layer 8 composed of a low melting point glass and a transparent protection layer which is not shown and composed of magnesium oxides are stacked in this order.
In order to improve contrast, vertical beltlike photo mask 9a as shown in FIG. 38, horizontal beltlike photo mask 9b as shown in FIG. 39, or lattice photo mask 9c is disposed in or out of transparent insulator layer 8 as photo mask 9. Each of photo masks 9a-9c has uniform width. Color filters may be disposed on photo masks 9a-9c in order to improve the tone of color as disclosed in JPA 9-61614.
On the other hand, data electrodes 2 composed of metal sheets are disposed on rear glass substrate 1 in column direction. Further, white insulator layer 3 composed of a low melting point glass containing titanium oxide particles and alumina particles is stacked on rear glass substrate 1 and data electrodes 2. Still further, partitions 4 composed of low melting point glasses are stacked on white insulator 3 in column direction. Each of spaces partitioned by partitions 4 has fluoresce 5a, 5b, or 5c which correspond to color emission of red, green, or blue.
Front grass substrate 6 and rear grass substrate 1 are stuck together so that pairs 7 of the scan electrode and common electrode intersect data electrodes 2. A pixel of a single color of red, green, or blue is formed at each of the intersecting points. Ultraviolet lights caused from discharge gas 10 which is enclosed inside and composed of rare gas excite fluoresce 5a, 5b, and 5c to emit lights, whereby a picture display is executed.
The first prior art is JPA 7-226945 entitled xe2x80x9cColor Plasma Displayxe2x80x9d in which a discharge space is narrowed to increase the number of appearing pixels and thereby to realize pseudo high definition of a picture without lowering emission efficiency. In the first prior art, each of the discharge cells of green is divided into two pieces so that the horizontal size of discharge cells of green becomes a half of the horizontal size of discharge cells of red and blue. Every second discharge cell of green in horizontal direction is shifted along vertical direction by a half of the vertical size of the cell.
The second prior art is JPA 8-190869 entitled xe2x80x9cPlasma Display Panelxe2x80x9d in which partitions are so designed that the area of blue or red becomes wider than the area of green, whereby the adjustment of color becomes easy.
In case that usual fluoresce is used for a plasma display panel, color purity deteriorates when pixels of red, green, and blue simultaneously emit lights or a color of white is displayed, because of imbalance of the brightness among red, green, and blue. In order to avoid the deterioration of color purity, discharge spaces of pixels are so adjusted that the discharge space of red becomes larger than the discharge space of green and the discharge space of blue becomes larger than the discharge space of red, or a drive circuit is so designed to generate drive signals which make the brightness of green low or brightness of blue high.
However, the method of adjusting discharge spaces of pixels has a disadvantage that improvement in drive method and fine design technique which are difficult to realize are required, because discharge characteristics of red, green, and blue become different from each other. The method of improving the drive signals has a disadvantage that the tone of color deteriorates when the level of a video signal rises, because the brightness of green which has been intentionally suppressed gradually rises.
In order to overcome the aforementioned disadvantages, the present invention has been made and accordingly, has an object to provide a plasma display panel apparatus in which shapes of photo masks with various and simple structures make an aperture area corresponding to a discharge space of red be wider than an aperture area corresponding to a discharge space of green, and an aperture area corresponding to a discharge space of blue be wider than an aperture area corresponding to a discharge space of red without complicating pixel structures and a drive method; color purity of white color emission is improved owing to appropriateness of balance of the brightness among red, green, and blue when pixels of red, green, and blue simultaneously emit lights; and deterioration of picture quality due to color shift is suppressed.
According to an aspect of the present invention, there is provided a plasma display apparatus comprising: discharge spaces of red which emit lights of red; discharge spaces of green which emit lights of green; discharge spaces of blue which emit lights of blue; and photo masks which are formed and arranged in order that an aperture of each of the discharge spaces of red may be wider than an aperture of each of the discharge spaces of green in area and an aperture of each of the discharge spaces of blue may be wider than the aperture of each of the discharge spaces of red in area.
The photo masks may comprise vertical photo masks. A width of each of vertical photo masks may vary in dependence on whether a corresponding discharge space is the discharge spaces of red, the discharge space of green, or the discharge space of blue. The vertical photo masks may include projections. The projections may be disposed on the discharge spaces of green and the discharge spaces of red, and the projections disposed on the discharge spaces of green may be wider than the projections disposed on the discharge space of red in area.
The photo masks may comprise horizontal photo masks. The horizontal photo masks may include projections. The projections may be disposed on the discharge spaces of green and the discharge spaces of red, and the projections disposed on the discharge spaces of green may be wider than the projections disposed on the discharge space of red in area.
The photo masks may comprise vertical photo masks and horizontal photo masks. A width of each of vertical photo masks may vary in dependence whether a corresponding discharge space is said discharge spaces of red, said discharge space of green, or said discharge space of blue. The vertical photo masks and the horizontal photo masks may be combined with one another. The vertical photo masks include projections. The projections may be disposed on the discharge spaces of green and the discharge spaces of red, and the projections disposed on the discharge spaces of green may be wider than the projections disposed on the discharge space of red in area. The horizontal photo masks include projections. The projections may be disposed on the discharge spaces of green and the discharge spaces of red, and the projections disposed on the discharge spaces of green may be wider than the projections disposed on the discharge space of red in area.
The photo masks may comprise discrete photo masks. The discrete photo masks may be disposed on the discharge spaces of green and the discharge spaces of red, and the discrete photo masks disposed on the discharge spaces of green may be wider than the discrete photo masks disposed on the discharge space of red in area.
The photo masks may comprise zigzag photo masks. The zigzag photo masks may be disposed on the discharge spaces of green and the discharge spaces of red, and the zigzag photo masks disposed on the discharge spaces of green may be wider than the zigzag photo masks disposed on the discharge space of red in area.
The photo masks may comprise diagonal photo masks. The diagonal photo masks may be disposed on the discharge spaces of green and the discharge spaces of red, and the diagonal photo masks disposed on the discharge spaces of green may be wider than the photo masks disposed on the discharge space of red in area.